CVE-2026-46644
symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload decodes to ASCII-only: insecure equivalence
Description
Symfony Polyfill backports PHP features and provides compatibility layers for extensions and functions. From 1.17.1 until 1.38.1, symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload is empty or decodes to ASCII-only code points because Idn::process() does not enforce the UTS #46 revision 33 requirement that decoded ACE labels contain at least one non-ASCII code point. Originally unequal domain names can be regarded as equal, which can lead to blacklist bypassing, inconsistent URL parsing, and server-side request forgery in applications using the polyfill to canonicalise or compare hostnames. This issue is fixed in version 1.38.1.
INFO
Published Date :
July 14, 2026, 9:16 p.m.
Last Modified :
July 14, 2026, 9:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-46644
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update symfony/polyfill-intl-idn to version 1.38.1.
- Verify domain name processing logic.
- Ensure proper hostname canonicalization.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-46644.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-46644 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-46644
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-46644 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-46644 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'symfony', 'product': 'polyfill', 'versions': [{'status': 'affected', 'version': '>= 1.17.1, < 1.38.1'}]}, {'vendor': 'symfony', 'product': 'polyfill-intl-idn', 'versions': [{'status': 'affected', 'version': '>= 1.17.1, < 1.38.1'}]}] Added Description Symfony Polyfill backports PHP features and provides compatibility layers for extensions and functions. From 1.17.1 until 1.38.1, symfony/polyfill-intl-idn accepts xn-- labels whose Punycode payload is empty or decodes to ASCII-only code points because Idn::process() does not enforce the UTS #46 revision 33 requirement that decoded ACE labels contain at least one non-ASCII code point. Originally unequal domain names can be regarded as equal, which can lead to blacklist bypassing, inconsistent URL parsing, and server-side request forgery in applications using the polyfill to canonicalise or compare hostnames. This issue is fixed in version 1.38.1. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-1289 Added Reference https://github.com/symfony/polyfill/commit/1be936e2491ccebe152bd736dfc91eb1422c8bec Added Reference https://github.com/symfony/polyfill/releases/tag/v1.38.1 Added Reference https://github.com/symfony/polyfill/security/advisories/GHSA-2xf4-cg6j-vhgq